The long term objective of this research is to evaluate the feasibility of applying genetic engineering to improvement of commercial aquaculture and mariculture. The specific aims of Phase I are to evaluate the effect of gene transfer techniques on egg hatching rate and transformation efficiency. Using a 3x2 factorial arrangement of treatments (Trt), gene transfer will be attempted by induced absorption of DNA during water hardening of the eggs (Trt I), by microinjection of DNA prior to fertilization (Trt II), and by microinjection of DNA into the germinal disc of fertilized eggs (Trt III). The DNA will consist of the metallothionein-thymidine kinase fusion plasmid (pMK) used as a complete linearized plasmid or a linear fragment containing the MT-I promoter/regulatory region and HSV TK structural gene. Plasmid structures consisting of the MT-I promoter and various other genes of interest, relative to aquaculture, are under investigation and may be available for the research. The hatching rates of treated and untreated eggs will be compared and the resulting fry will be sacrificed for tissue analysis of gene integration and expression. Successful development of gene transfer procedures in fish will be important as a model system for future research in eukaryotic genetics. These procedures will also be important for potential improvement in productivity of various fish and crustaceans in commercial fish farming.